Holocene evolution of Hans Tausen Iskappe (Greenland) and implications for the palaeoclimatic evolution of the high Arctic

In this study the Holocene evolution of Hans Tausen lskappe (Peary Land, North Greenland) is investigated. Constraints on the ice cap evolution are combined with climatic records in a numerical ice flow surface mass balance (SMB) model to better understand the palaeoenvironmental and climatic evolution of this region. Our simulations suggest that after disconnecting from the Greenland Ice Sheet (GrIS) the ice cap had roughly its present-day size and geometry around 9-8.5 ka BR During the Holocene Thermal Maximum (HTM) the southern part of the ice cap is modelled to collapse, while the northern part of the ice cap survived this warmer period. The late Holocene regrowth of the ice cap to its maximum Neoglacial extent at the end of the Little Ice Age (LIA) can be reproduced from the temperature reconstruction. The simulations suggest that over the last millennia the local precipitation may have been up to 70-80% higher than at present. By coupling the pre-industrial temperature forcing to a post-LIA warming trend, it is suggested that the warming between the end of the LIA and the period 1961-1990 was between 1 and 2 degrees C. In all experiments the ice flow model complexity and horizontal resolution have only a minor effect on the long-term evolution of the ice cap. We further conclude that the glacial isostatic adjustment has a significant effect on the modelled Holocene ice cap evolution. This suggests that modelling studies of millennial-scale ice cap evolution should focus on SMB and boundary conditions, rather than on complex ice dynamics. (C) 2017 Elsevier Ltd. All rights reserved.